1. Field of the Invention
The present invention relates to an image forming apparatus having a media cartridge for forming an image, wherein color corrections are made for forming a full color image according to the sensitivity of a light receiving sheet accommodated in the media cartridge.
2. Description of the Prior Art
Japanese Laid-Open Patent Publication No. 5888739 discloses an image forming method using a light receiving sheet coated with microcapsules enclosing photopolymerizable materials and image forming materials and an image receiving sheet coated with developer that reacts with the image forming materials to produce colors.
The forming of an image according to the above method proceeds as follows: when the light of an original image is projected onto the light receiving sheet, the microcapsules harden where the light strikes, resulting in a selectively hardened image. Then, the image receiving sheet coated with developer is placed over the light receiving sheet on which the selectively hardened image is formed, and pressure is applied. Application of pressure causes non-hardened microcapsules to rupture and therefore, the image forming materials enclosed therein to flow out to react with the developer on the image receiving sheet, thus producing colors and developing the image in a simple process.
To prevent the microcapsules from rupturing by an external force or being exposed to external light before the exposure process, the light receiving sheet is accommodated in a cartridge. Generally, the cartridge is in the form of a roll and with a loading leader sheet connected to the leading edge thereof, the cartridge being set in the image forming apparatus in a detachable way.
A light receiving sheet used in a pressure-and photo-sensitive image forming method such as described above is coated with a single kind of microcapsule for monochrome image forming, and coated with three kinds of microcapsules for full color image forming, i.e., microcapsules of yellow, cyan, and magenta.
As described, the light receiving sheet corresponds to a photoconductor in a conventional image forming apparatus. The sensitivity of the light receiving sheet is a vital factor determining the copy quality. Specifically, in the case of a light receiving sheet for full color image forming, the individual sensitivities of the above-mentioned three kinds of microcapsules, yellow, cyan, and magenta, as well as the whole sensitivity, become the major points to be considered.
However, it is extremely difficult to produce light receiving sheets having exactly the same sensitivity because of differences in their manufacturing and environmental conditions. For example, light receiving sheets coated with three kinds of microcapsules must be made so as to have the same characteristics with respect to the whole sensitivity as well as the individual sensitivities of these three kinds of microcapsules. Variation in sensitivity characteristics between production lots is therefore unavoidable.
Variation in sensitivity characteristics between production lots means that each time a new cartridge is loaded in an image forming apparatus, the operator must make adjustments of copy quality according to the unknown sensitivity characteristics inherent in that particular cartridge. To make the adjustments, the operator must make a number of test copies, changing the amount of exposure and color correction filters for each image forming, which requires manual operation to set proper values. Thus, the prior art has had the difficulty in adjusting the color density, color corrections, etc., particularly in full color image forming, imposing manual difficulties on the operator. The prior art has also had the difficulty of requiring a lot of time and a number of image forming operations because of manual adjusting work, wasting time and copy cost and requiring skilled work that anyone cannot do with ease.